I'm looking at the documentation of RTTI which says:
If RTTI generation is enabled, the resulting binary includes special metadata that contains information about types (for example, class ancestry, declared fields, annotated attributes).
Where is the RTTI metadata stored in the PE file, and what structure does it have?
Windows PE files do not have a standard section where RTTI is stored, its format and where it is stored is completely up to the compiler vendor.
Even though it does not specify the storage format (only the memory layout) the Itanium C++ ABI specification is a good place to start and then move on to the GCC source code if you want to know more. This answer reveals that GCC v3+ uses this ABI everywhere except Windows where I'm guessing they try to follow the Microsoft format instead.
The specifics should not matter that much because the compiler is free to change its implementation at any time and you would have to investigate a specific version if you want to interact with its RTTI data.
For Delphi specific information it might be worth taking a look at the Free Pascal code but I don't know if they are fully ABI compatible.